DATING FELDSPAR USING POST-ISOTHERMAL LUMINESCENCE AND APPLICATION TO CLIMATE-SENSITIVE PALEOENVIRONMENTS

利用等温后发光测定长石的年代及其在气候敏感古环境中的应用

• 批准号: RGPIN-2018-06422
• 负责人: Lamothe, Michel
• 金额: $ 3.72万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=690243
• 关键词: DATING; FELDSPAR; USING; POST; ISOTHERMAL

Our planet is facing a critical part of its history as modern societies need to implement adaptation strategies to rapidly changing surface environments in response to global warming. Using the past to better apprehend the future, one should take advantage of the geological record as it contains archives that can be used to interpret the resilience or sensitivity of physical environments to climate change. These archives are represented mainly by sediments and in order to be accurately interpreted, they need to be inserted in a proper time-frame, hence dated. The main objective of this research program is therein to develop new dating methodologies in the field of feldspar luminescence for assessing the chronology of climate-sensitive geological and archaeological sedimentary archives. ***The scientific approach is to focus on the luminescence properties and the phenomenology of single feldspar grains in sediments. Due to the nature of its solid-state physics, luminescence dating of feldspar shall be applicable to a large part of the last million years of Earth history. This method can therefore probe one order of magnitude deeper into geological time than radiocarbon and more than 5 times the current age range of quartz optically-stimulated luminescence, routinely used in luminescence dating. Our recent work as resulted in the development of an innovative protocol in which low-temperature IRSL following post-isothermal treatments is shown to yield ages in accordance with the stratigraphical assignment for several samples from different parts of the world. This novel approach is now possible following the development of new instrumentation in luminescence readers, most of these are now available in the Montréal laboratory as a result of a major CFI funding to the UQAM geochronology group. This innovation shall provide precise as well as accurate age determinations as no correction for fading is needed. ***The detailed methodology is two-fold. 1) In order to develop a new method, laboratory protocols have to be devised and implemented, that will investigate the phenomenology of feldspar luminescence. This research shall contribute to HQP training for laboratory-focused and physics-inclined students. 2) These innovative methodologies will then be tested and validated in climate-sensitive geological contexts: a) “warm” interglacial coastal sediments, indicators of high sea level (e.g. USA, Brazil, Morocco), b) “cold” periglacial features (e.g. Yukon, Alaska). HQP training is strongly entangled in the specific research projects for field-oriented Earth sciences students.***The novelty of this research and its upmost significance is in offering new ideas and concepts to the luminescence dating field as well as providing access to a new chronological tool for the natural sciences community involved in the science of Global Changes.

我们的星球正面临着其历史的一个关键部分，因为现代社会需要针对快速变化的地表环境实施适应策略，以应对全球变暖。人们应该利用过去来更好地理解未来，因为它包含着档案。可用于解释自然环境对气候变化的恢复力或敏感性。这些档案主要以沉积物为代表，为了准确解释，它们需要插入适当的时间范围内，因此是主要目标。该研究计划的目的是开发新的长石发光领域的测年方法，用于评估气候敏感的地质和考古沉积档案的年代学***由于沉积物的性质，科学方法是关注沉积物中单个长石颗粒的发光特性和现象学。由于其固态物理学，长石的发光测年法适用于地球历史最后一百万年的大部分时间，因此这种方法可以比放射性碳等更深入地探测一个数量级的地质时间。我们最近的工作导致了一种创新方案的开发，其中等温后处理后的低温 IRSL 的年龄范围是常规石英光激发光年龄范围的 5 倍以上。随着发光读数仪新仪器的开发，这种新颖的方法现在可以对来自世界不同地区的多个样本进行地层分配，由于主要的 CFI，其中大部分现已在蒙特利尔实验室可用。为 UQAM 地质年代学小组提供资金。这项创新将提供精确且准确的年龄测定，因为不需要对褪色进行校正。 ***详细的方法有两个方面 1) 为了开发一种新方法，实验室协议已制定。待设计和实施，这将研究长石发光的现象学。这项研究将有助于针对以实验室为重点和有物理学倾向的学生的 HQP 培训。2) 这些创新方法将在 2017 年进行测试和验证。气候敏感的地质环境：a）“温暖”的冰间沿海沉积物，强烈预示着高海平面（例如美国、巴西、摩洛哥），b）“寒冷”的冰缘特征（例如育空地区、阿拉斯加）。面向领域的地球科学学生的具体研究项目。***这项研究的新颖性及其最重要的意义在于为发光测年领域提供了新的想法和概念，并提供了获得新知识的途径为参与全球变化科学的自然科学界提供的按时间顺序排列的工具。